Extension Search / Soil Labs / South Carolina
Clemson University Agricultural Service Laboratory
Clemson University runs South Carolina’s public soil testing program. Send a soil sample and you get back your pH and nutrient levels, and what each number means for your plants.
Lab Details
Clemson University
Clemson, South Carolina
- Basic test
- Organic matter
- Nitrate
- Salts
- Micronutrients
- CEC
Open the lab's site for fees, forms and the mailing address.
Test Methods
This lab uses:
- Phosphorus: Mehlich-1. An older acid extract, still used in parts of the Southeast on sandy, acid soils.
- Potassium: Mehlich-1. An older acid extract, still used in parts of the Southeast on sandy, acid soils.
Labs pull nutrients out of soil with different chemicals, and each one gives a different number for the same soil. 20 ppm on one test and 20 ppm on another don’t mean the same thing, so check which test your report used before you compare it to a chart.
Tests
- Basic test. pH, phosphorus and potassium, usually with calcium and magnesium. Enough for most gardens and lawns.
- Organic matter. How much organic matter the soil holds, which sets how much nitrogen it releases.
- Nitrate. Nitrate nitrogen in the soil now. Most useful in dry climates, where it carries over winter.
- Salts. Soluble salts (EC), and sodium where salt or poor drainage is a problem.
- Micronutrients. Zinc, iron, manganese and copper, sometimes boron.
- CEC. Cation exchange capacity: how many nutrients the soil can hold on to.
- The standard test covers pH, phosphorus, potassium, calcium, magnesium, zinc, manganese, copper, boron and sodium, with lime need and CEC.
- Drop samples at a county Extension office, or mail them to the lab with the form and payment.
- A mailer kit with a prepaid return envelope can be ordered online.
Sources: [1] [2]
Out of State
The lab’s site doesn’t say whether it takes samples from other states. Ask before sending one.
Sample Tips
- Take 10 or more small cores across the area and mix them in a clean bucket. One spot tells you about one spot.
- Sample gardens and lawns about 6 inches deep, below any mulch or thatch.
- Keep beds that are grown differently, like a lawn and a vegetable garden, as separate samples.
- Wait a couple of months after fertilizing or liming, so the test reads the soil and not the last bag.
- Use the same lab and the same tests each time, so the numbers compare from year to year.
Your county South Carolina Extension office can help you take the sample and read the report.
Results
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